Field of the Invention
The present invention relates to an iron golf club head and a golf club.
Description of the Background Art
One of capabilities required of iron golf clubs is high restitution performance. In conventional iron golf clubs, a high strength material, such as chromium molybdenum steel (chromoly steel) or maraging steel, for example, is used to reduce the thickness of a face, thereby achieving high restitution performance.
In the sales market of iron golf clubs, custom fitting for adjusting the lie and/or loft angles in accordance with golfer's swing is widely available. In the custom fitting, a skilled craftsman adjusts the lie and/or loft angles to golfer's desired angles by bending a neck portion of a golf club head.
Here, a high strength material such as chromoly steel is not suited for custom fitting because it is difficult to bend a neck portion made of such a material due to its hardness. Conventionally, a face member and a head body are therefore made of different materials from each other and are welded together to enable angle adjustment of an iron golf club head manufactured through the use of a high strength face material.
Japanese Patent No. 4331635 discloses performing quenching processing only on the face portion after molding chromoly steel by forging to thereby increase hardness of the face portion and to bring the hardness of the neck portion into a level that enables angle adjustment.
In the conventional iron golf club head in which the face portion and the body portion are bonded by welding, however, there is a possibility that a welded portion may become cracked during angle adjustment. Moreover, when the face portion and the body portion are molded by forging separately, the grain flow produced in the forging step is not integral from the body portion including the face to the neck portion. Thus, one cannot feel a good hitting feeling specific to forged iron.
Furthermore, in the iron golf club head described in Japanese Patent No. 4331635, the neck portion has a hardness of HRC 18 to 20 and enables angle adjustment, whereas its workability is actually not necessarily good.